Major morphological feature of the reserve is the Uvac River canyon valley including the valleys of its tributaries. The right tributaries to Uvac are Vapa, Kladnička reka, Vrševina and Tisovica rivers and left- Čajak, Veljušnica and Zlošnica.
The Uvac river waters deeply carved its bed eroding limestone rocks to form narrow canyon valleys with high, steep limestone cliffs. Canyon parts within the reserve are located between the confluence of Vapa and Veljušnica rivers and down the river from Kokin Brod on. The middle part between Veljušnica and Kokin Brod has characteristics of a gorge. The average depth of the valleys ranges between 200 and 300 m, maximum up to 350m.
The special value of the canyon parts of the valley are curving meanders. A very impressive zone with these meanders is upstream of Veljušnica mouth, in the limestone zone of Lopiže village. Relative height of meander heads is 100m.